A novel anti-infective approach is being utilized to exploit stresses already imposed on invading organisms in vivo. Iron (Fe) metabolism is a key vulnerability of infecting bacteria because organisms require Fe for growth. Studies may indicate that possibly a "Trojan horse" strategy that uses the metal gallium (Ga) to disrupt bacterial Fe metabolism holds promise as an antimicrobial approach. Due to its chemical similarity to Fe, Ga can substitute for Fe in many biologic systems and inhibit Fe-dependent processes. Data may show that Ga kills the opportunistic pathogen Pseudomonas aeruginosa (including antibiotic resistant strains), may be active against biofilms, and may treat three different model P. aeruginosa infections. Ga may be a promising new therapeutic for P. aeruginosa infections. A pharmacokinetic and safety study of intravenous (IV) Ga in subjects with cystic fibrosis (CF) is being proposed as chronic P. aeruginosa airway infections are the major cause of death in these patients and few treatments exist.